The Palatka daily news. (Palatka, Fla.) 1884-1888, 1887-04-20
PHOTOTYPIC WORK.
SOMETHING ABOUT THE VARIOUS
PROCESSES NOW EMPLOYED.
The Methods of GouPiI. in Paris-ouiek-
ness of American Processes-The Ac-
tion of Light Scnsitized GeIatine-
PhotOgrayure.

The most common forms of reproductive
art nowadays are those based on phOtog-
raphy, ami it may not De generally known
that the most extensive concern i'll the
country that j. devoted to this kind of
work is housed in Brooklyn. The com
pany who controls these works and give
employment To II considerable number of
operatives some of whom are To be re-
larded rs artists rather than mechanics,
for into the finishing and printing of the
plates taste ~ well as skill must enter.
The house of GOUp.l in Paris, has until
recent years enjoyed almost monopoly
of photoGravUTc, and its work has celeb
rity for strength and clearnesS. The
GOupil process is secret, but it is cvi-
dent from the length of time taken to
prepare q plate, ami from the appearance
of sItndry lines and markings that would
not commonly show in a solar print, that
hand work i nearly as important Il fac
tor as chemical evolution The company
here in Brooklyn FINISHES "A plate in as
nIany hours rs days are taken by the
Goupil firm, AMI the results are in many
instances surprising Advances in the
art are still to he made, but there is a
broad foundation 10 work upward from.
There are dozens If names for what is
substantially the same process-the photo
type, photopriut, rtnsStype, albertype,
artotype, Hchtdruh, hciiotype, carbon
print, autp.glS pin, Ives process, Nielsen
bach process, photo lithograph, photo
caustic print, photo gelatine print, photo
engraving, zinc etching and photogra-
vure. The action of light on sen>itiZed
gelatiIe or other material il the occasion
of all these forms. GCldtine il made sen
sitive by treatment with biChromate Of
potash, which likewise renders il insol-
uble 10y water, and in this condition it
will take grease, when that Is applied,
He 4. \.
Photographic negative the effect Of light
striking thr0U-'. the glass is to close the
pores of the Gtiatine and harden it, and
where light does not act the gelatine be
comes soft and absorbent. After the
sheet has received the impress from the
negative a greasy ink will adhere to the
hard portions, while the sponge areas
/ being kept moist with water, refuse it,
You apply your ink, lay a piece of paper
on it, stamp il, the ink comes off on the
paper and there i Your picture-a hello
type, in commercial phrase.
APPLIED To STONE PRINTING
This process il much the same as lith-
ography, but the photographic stone holds
grease only where there are decided lines,
I while gelatine receives the impress of a
I hundred gradations of light and shade.
l Photography is applied TO stone printing
where anything is To be represented by
/ clean masses of black ami white, and it is
( therefore useful for copying maps, plans,
tracings, ink drawings, designs, miniature
| calendars, papers and catalogues, line en-
7 cravings, autograph letters. aud so ON.
! In that case paper coated with gelatine il
/ printed on by a negative, i'll the cases
I of an ordinary photograph. and the grease
! taking lines are transferred bodily to the
\ stone. When the ink lines are transferred
/ to zine instead OF stone and the exposed
/ portions of the metal are eaten down by
/ acid, leaving the lines in relief, plate is
4 made that Is similar to a stereotype and
this form is commonly used for cheap il
/ Illustrations in daily papers \ plaster
b cast may be taken from a gelatine i'm
\ press after the lines have set, and from
this may be made metal plate that will
( print what are called photo engravings.
For a phOtogravure biChromatized CELIA
/ tine Is mixed with sand or emery dust, the
/ picture is thrown on il from "A negative
I the grease taking lines harden. the light
/ portions are swollen with water and
Y copper she'll Is deposited ON il as an electro
I type. The sand gives a grain TO the sur
/ face and holds the ink where il is deSir-
/ able TO iTapa,rt n half tint In the hands
/ of a sSillfUl printer proof pEotoGravure
\ can be made almost - strong as an etCh-
/ ing, "a il ! easy 10 wipe out the high
/ lights until they cre represented by the
I actual wLiJenesS Of the paper that re-
Z CtINtN tlit Eit+t' t~tt lNIt~ Gnu masses
I of shadow axe uhtaIuahle by leaving films
/ of ink Of les ~ greater density on the
1 metal surface.-BTuoklyn Eagle.
An English food inspector, Mr. James
! Bell, finds that horse flesh and beef can
/ not be positively distinguished by external
| appearance. but that the fat II reliable
test The horse fat IS fluid AZ a tempera-
/ ture of seventy degs, and has a specific
gravity at 100 degs- Of about s.jOc- !;
while the fat of beef rnelts at ITO to 100
degs, and is considerably lighter The
low melting point OF the fat viii show
! when sausages are made from horse meat.